Evaluation of volatile compounds and free fatty acids in set types yogurts made of ewes’, goats’ milk and their mixture using two different commercial starter cultures during refrigerated storage

► The yogurts with high acetaldehyde had low diacetyl content, pH value and high TA. ► Ewes’ milk yogurt contained the lowest amount of acetaldehyde. ► Culture YF-3331 produced both more diacetyl and SCFFAs than culture CH-1. ► The total level of SCFFAs was the highest in ewes’ yogurt. ► SCFFAs reached a maximum level at the end of storage while LCFFAs decreased. Six different types of yogurt were manufactured from Damascus goat milk, Awassi ewe milk and a mixture of equal portions of the 2 species of milk using 2 types of commercial yogurt cultures (CH-1 and YF-3331). Yogurts were chemically analysed at 1, 7, 14 and 21days of storage. Results showed that cultures significantly affected acetaldehyde (P